batman-adv: fix skb deref after free

commit 63d443efe8be2c1d02b30d7e4edeb9aa085352b3 upstream.

batadv_send_skb_to_orig() calls dev_queue_xmit() so we can't use skb->len.

Fixes: 953324776d6d ("batman-adv: network coding - buffer unicast packets before forward")
Signed-off-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index fb0c4e6069a7a6cd5cfeb88079be4602e0d35d29..51993a9f686c05138f111fadb53df7d4ad3c130a 100644 (file)
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -568,6 +568,7 @@ static int batadv_route_unicast_packet(struct sk_buff *skb,
        struct batadv_unicast_packet *unicast_packet;
        struct ethhdr *ethhdr = eth_hdr(skb);
        int res, hdr_len, ret = NET_RX_DROP;
+       unsigned int len;
 
        unicast_packet = (struct batadv_unicast_packet *)skb->data;
 
@@ -608,6 +609,7 @@ static int batadv_route_unicast_packet(struct sk_buff *skb,
        if (hdr_len > 0)
                batadv_skb_set_priority(skb, hdr_len);
 
+       len = skb->len;
        res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
 
        /* translate transmit result into receive result */
@@ -615,7 +617,7 @@ static int batadv_route_unicast_packet(struct sk_buff *skb,
                /* skb was transmitted and consumed */
                batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
                batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
-                                  skb->len + ETH_HLEN);
+                                  len + ETH_HLEN);
 
                ret = NET_RX_SUCCESS;
        } else if (res == NET_XMIT_POLICED) {